Excalidraw Canvas MCP server on WSL. Node.js (v20) Express + WebSocket app serving live diagram canvas. Managed by systemd (excalidraw_canvas.service) via execution standard. Watcher pair (excalidraw_canvas-watcher.path) watches dist/, package.json, start.sh. Prod code at /home/rohan/prod/excalidraw-mcp/. NO vivo rule — deployment gap, must be addressed separately.